Who did you talk to? I pulled this from Magnuson's FAQ page of their website:

"Is there any maintenance required with my kit? Do I need to change the oil in it? A big advantage of our kits is the lack of any scheduled maintenance. The only item to keep an eye on is the drive belt. Just as any drive belt, if it shows any signs of wear, immediately replace it. The nose oil, however, has a service life of 80,000 miles."

And I know I have seen Brian (BlownChevy) post several times that there is no maintenance necessary unless you hit 100K miles, when you should send it back to them to have it checked out and some parts rebuilt.